Quaternion targetRotation = Quaternion.LookRotation(this.direction_move);
transform.localRotation = this.Slerp(transform.localRotation,targetRotation,0.15f);
// -----------------------
public Quaternion Slerp(Quaternion q1, Quaternion q2,float t) {
	float d = Quaternion.Dot(q1,q2);
	if (d < 0) {
		q2.x *= -1.0f;
		q2.y *= -1.0f;
		q2.z *= -1.0f;
		q2.w *= -1.0f;
	}
	return Quaternion.Slerp(q1,q2,t);
}